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Enhancing active electro-kinetic micro-mixer efficiency by introducing vertical electrodes and modifying chamber aspect ratio
, Article Chemical Engineering and Processing - Process Intensification ; Volume 142 , 2019 ; 02552701 (ISSN) ; Sani, M ; Saidi, M. S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Micro-mixers are considered as vital components of Micro Total Analysis systems (μTAS). Major objective in the design of micro-mixers is achieving high mixing quality in short mixing times. In this paper, numerical simulation of some micro-mixer designs has been carried out to understand the detailed flow pattern and thereby to propose modifications for improving mixing efficiency. It is well known that inducing convection will provide turbulent like behavior with corresponding mixing enhancement. In micro systems to drive the flow, electro-osmotic force is usually used by introducing electrodes. In this work, mixing electrodes have been implemented to induce convection and eddies. This...
Dynamic Simulation of Wettability Alteration Induced by Low-Salinity-Effect: Study of Phenomena within Thin Water Film
, M.Sc. Thesis Sharif University of Technology ; Mahani, Hassan (Supervisor) ; Joekar Niasar, Vahid (Co-Supervisor)
Abstract
Recent experimental studies have demonstrated that the lowering of brine could alter the wettability of the oil-brine-rock systems from an oil-wetting state toward a more water-wetting state. This so-called “Low-salinity effect” (LSE) is one of the main effects of the enhanced oil recovery technology based on low-salinity waterflooding. “Double layer expansion” (DLE) in the thin brine film is proposed as the principal mechanism of this phenomenon. Nonetheless, the role of the electrical behavior of the oil/brine and rock/brine interfaces on the kinetics and dynamics of this process is not well understood. Moreover, since most of the previous works have either dealt with a thin film at...
Impact of oil polarity on the mixing time at the pore scale in low salinity waterflooding
, Article Energy and Fuels ; Volume 34, Issue 10 , 16 September , 2020 , Pages 12247-12259 ; Mahani, H ; Ayatollahi, S ; Niasar, V ; Sharif University of Technology
American Chemical Society
2020
Abstract
The efficiency of low salinity waterflooding, particularly during tertiary mode injection, is highly controlled by in situ mixing between the stagnant regions holding high salinity water (HSW) and the flowing regions containing low salinity water (LSW) because it impacts directly the electrokinetics of wettability alteration and the time scale of the low salinity effect. This study aims to address the effects of oil polarity and charged rock surfaces on the time scale of mixing and transport under two-phase flow conditions. A systematic series of micromodel experiments were performed. The micromodels were first saturated with high salinity formation brine and oil (both model and crude oil);...